1. Field of the Invention
The present invention relates to an electronic fluid pump.
2. Background Art
Use of fluid pumps in vehicle engine cooling systems and various industrial applications is well known. However, typical fluid pumps in both of these areas have inherent limitations. Typically in engine cooling systems, a coolant pump has a pulley keyed to a shaft. The shaft is driven by the engine via a belt and pulley coupling, and rotates an impeller to pump the working fluid. Fluid seals sometimes fail due to the side load from the drive belt, which tends to allow fluid to leak past the seal into the bearing.
U.S. Pat. No. 6,056,518, issued to Allen et al. on May 2, 2000, describes one attempt to overcome the shortcomings of prior art vehicle coolant pumps. The ""518 patent provides a fluid pump with a switched reluctance motor that is secured to a housing and rotates an impeller for pumping the fluid. This design eliminates the side load problem associated with keyed pulleys, but it is generally not intended for use where larger industrial pumps are required.
Industrial pumps are typically driven by an electric motor connected to the pump via a coupling, the alignment of which is critical. Misalignment of the coupling can result in premature pump failure, which leads to the use of expensive constant velocity couplings to overcome this problem. Moreover, industrial pump motors are typically air-cooled, relying on air from the surrounding environment. The cooling air is drawn through the motor housing leaving airborne dust and other contaminants deposited in the motor components. These deposits can contaminate the bearings, causing them to fail, or the deposits can coat the windings, shielding them from the cooling air and causing the windings to overheat and short out.
Accordingly, it is desirable to provide an improved fluid pump which overcomes the above-referenced shortcomings of prior art fluid pumps, while also providing enhanced fluid flow rate and control capability while reducing costs.
One aspect of the present invention provides an improved fluid pump with enhanced fluid flow rate and control capability that also reduces costs.
Another aspect of the invention provides a fluid pump that comprises a housing that has a housing cavity with an inlet and an outlet. A diffuser, at least a portion of which is attached to the housing, is substantially disposed within the housing cavity. The diffuser has an internal diffuser cavity, in which an electric motor stator assembly and a tubular member are located. The tubular member sealingly contacts the diffuser to isolate the stator assembly from the working fluid. An impeller is rotatably disposed near the inlet of the housing cavity. An electric motor rotor assembly is substantially and rotatably disposed within the tubular member, and it is connected to the impeller for pumping the fluid from the inlet to the outlet.
Yet another aspect of the invention provides a fluid pump that comprises a housing having a housing cavity with an inlet and an outlet. A diffuser having an internal diffuser cavity is substantially disposed within the housing cavity, and has at least a portion that is attached to the housing. An electric motor stator assembly and a tubular member are disposed within the diffuser cavity. The tubular member is in sealing contact with the diffuser; this isolates the stator assembly from the fluid. An impeller is rotatably disposed near the housing cavity inlet. A rotor having first and second sides is rotatably disposed within the tubular member, and a rotor shaft is attached to the rotor and connected to the impeller for pumping the fluid from the inlet to the outlet.
A further aspect of the invention provides a housing having a housing cavity with an inlet and an outlet. A diffuser, at least a portion of which is attached to the housing, is substantially disposed within the housing cavity. The diffuser includes an internal diffuser cavity, in which an electric motor stator assembly and a tubular member are located. The generally cylindrical tubular member forms a seal with the diffuser that isolates the stator assembly from the fluid. An impeller is rotatably disposed near the inlet of the housing cavity, and a rotor is rotatably disposed within the tubular member. The rotor has a rotor shaft that is attached to the impeller for pumping the fluid from the inlet to the outlet. The rotor shaft is supported within the tubular member by a shaft support apparatus. A circuit board assembly for controlling the pump is disposed within the diffuser cavity; it is electrically connected to the stator assembly and isolated from the fluid by the tubular member.